#include<iostream>
#include<vector>
using namespace std;

int main()
{
	vector<vector<int> > v = { {1,2,3,4} , {5,6,7,8} ,{9,10,11,12} };
	for (int i = 0; i < v.size(); i++)
	{
		for (int j = 0; j < v[i].size(); j++)
		{
			cout << v[i][j] << endl;
		}
	}
	return 0;
}